Purpose
To measure the choroidal thickness (ChT) using enhanced depth imaging (EDI) from spectral domain optical coherence tomography (SD-OCT) in subjects of different age and refractive errors.
Methods
One hundred and twenty subjects were recruited including children aged 5 to 12 years (18 emmetropes, 19 low myopes and 16 moderate myopes), age and gender matched emmetropic (n = 28) and myopic (n = 28) young adults, and myopic anisometropes (n = 11). ChT was measured along the horizontal meridian at subfoveal, 1mm and 3mm nasal, and 1mm and 3mm temporal to fovea.
Results
In the children group, subfoveal ChT significantly reduced with age and axial length in univariate analyses. Multivariate analysis demonstrated only the effect of axial length (p = 0.001, r = -25.5, beta coefficient = -0.50). Subfoveal ChT reduced at 28.2 microns per 1mm of axial elongation. In the young adult group, subfoveal ChT reduced at 32.4 microns per 1mm of axial length. The slopes of the regression equations were similar between the children and young adult groups (ANOVA: p = 0.61). The trend of ChT asymmetry varied between the two groups. Increase in myopia resulted in ChT thinning more at the subfoveal than the peripheral regions in the young adult group, while ChT thinning was more at the temporal region in the children group. In the myopic anisometropic group, subfoveal ChT reduced at a great rate of 58.9 microns per 1mm difference in axial length. The ChT thinning was mainly at the subfoveal region in the higher myopic eye.
Conclusions
The ChT varied with the eyeball size. Its variation was different between children and adult. Potential contributing factor might be variation of posterior eye shape during myopia development.
Keywords: 605 myopia •
452 choroid